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Influence of solvent in solvothermal synthesis of Cu3SnS4: Morphology and band gap dependant electrocatalytic hydrogen evolution reaction and photocatalytic dye degradation
摘要： Cu3SnS4 (CTS) with various morphologies have been synthesized via solvothermal method. The influence of different solvents such as deionized water (CTS-DI), N,N-dimethylformamide (CTS-DMF) and poly ethylene glycol (CTS-PEG) has been investigated. XRD patterns of all the prepared samples exhibit tetragonal structure with preferential orientation along (1 1 2) direction. It is found that the solvents play a key role to tune the morphology and band gap. The morphology varied as irregular sheet like structure, mesoporous structure and feather like structure for CTS-DI, CTS-DMF and CTS-PEG, respectively. The band gap was found to be 1.33, 1.65 and 1.19 eV for CTS-DI, CTS-DMF and CTS-PEG, respectively. Electrocatalytic hydrogen evolution reaction and photocatalytic dye degradation of MB were tested using the prepared CTS samples. As an electrocatalyst or photocatalyst, it is found that CTS-DMF with mesoporous structure shows an enhanced catalytic activity with lower overpotential, a smaller Tafel slope (88 mV/dec), high stability in acidic medium and an enhanced photocatalytic activity. A more realistic mechanism for the photocatalytic activity of CTS-DMF is proposed.
关键词： Solvothermal,Cu3SnS4,Electrocatalyst,Photocatalyst
更新于2025-09-09 09:28:46
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Magneto-structural properties and photocatalytic performance of sol-gel synthesized cobalt substituted Ni Cu ferrites for degradation of methylene blue under sunlight
摘要： In this study, Ni0.5-xCoxCu0.5Fe2O4 (with x varying from 0.0 to 0.5) ferrites have been synthesized by a sol-gel auto-combustion method using urea as fuel. The influence of Cobalt (Co2+) content on the structural, optical and magnetic Ni-Cu ferrites was studied by X-ray diffraction (XRD) patterns, Fourier Transform Infrared Spectroscopy (FT-IR), UV-Vis Spectroscopy (UV-DRS) and vibrating sample magnetometer (VSM). Scanning electron microscopy (SEM) and Energy dispersive X-ray (EDX) analysis have been used to determine morphology and compositions respectively. The X-ray diffraction studies have been carried out by considering the distance between adjacent crystal planes, lattice constant and average crystallite size which decrease from 44-35 nm with substitution of Co2+. FT-IR spectra show two major stretching bands around 400-600 cm-1. The magnetic parameters were measured at room temperature where increase in saturation magnetization was observed with increase in concentration of Co2+ in Ni-Cu ferrites. The photocatalytic performance study of Co2+ substituted Ni-Cu ferrites was carried out under visible and direct sunlight on methylene blue (MB) dye. The increase in degradation percentage was observed with Co2+ substitution in both visible and sunlight. The catalyst was found to be more efficient in sunlight with 91% degradation of MB within 120 minutes.
关键词： SEM,VSM,Ni-Co-Cu Ferrites,XRD,Sol-Gel Auto-Combustion,Photocatalyst
更新于2025-09-09 09:28:46
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Environmental disinfection with photocatalyst as an adjunctive measure to control transmission of methicillin-resistant Staphylococcus aureus: a prospective cohort study in a high-incidence setting
摘要： Background: Environmental disinfection with continuously antimicrobial surfaces could offer superior control of surface bioburden. We sought to decide the efficacy of photocatalyst antimicrobial coating in reducing methicillin-resistant Staphylococcus aureus (MRSA) acquisition in high incidence setting. Methods: We performed prospective cohort study involving patients hospitalized in medical intensive care unit. A titanium dioxide-based photocatalyst was coated on high touch surfaces and walls. Five months of pre-intervention data were compared with five months of post-intervention data. The incidence rates of multidrug-resistant organism acquisition and the rates of hospital-acquired blood stream infection, pneumonia, urinary tract infection, and Clostridium difficile–associated diseases were compared using Cox proportional hazards regression analysis. Results: In total, 621 patients were included. There was significant decrease in MRSA acquisition rate after photocatalyst coating (hazard ratio, 0.37; 95% confidence interval, 0.14–0.99; p = 0.04). However, clinical identification of vancomycin-resistant Enterococcus spp. and multidrug-resistant Acinetobacter baumannii did not decrease significantly. The hazard of contracting hospital-acquired pneumonia during the intervention period compared to baseline period was 0.46 (95% confidence interval, 0.23–0.94; p = 0.03). Conclusions: In conclusion, MRSA rate was significantly reduced after photocatalyst coating. We provide evidence that photocatalyst disinfection can be an adjunctive measure to control MRSA acquisition in high-incidence settings. Trial registration: ISRCTN Registry (ISRCTN31972004). Registered retrospectively on November 19, 2018.
关键词： Environmental disinfection,Hospital-acquired infection,MRSA,Photocatalyst
更新于2025-09-09 09:28:46
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Novel photocatalyst nitrogen-doped simonkolleite Zn5(OH)8Cl2·H2O with vis-up-conversion photoluminescence and effective visible-light photocatalysis
摘要： As photocatalysts exhibit selectivity toward various pollutants, it is necessary to develop different and novel photocatalysts. In this work, a novel photocatalyst-nitrogen-doped simonkolleite Zn5(OH)8Cl2·H2O (DSM) is prepared through a new facile method: calcinating the mixture of zinc hydroxide, urea, and guanidine hydrochloride at 575?°C for 1?h in a furnace with an air atmosphere. The as-prepared sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectra, UV–visble near-infrared diffuse reflection spectra (UV–Vis–NIR DRS), Brunauer–Emmett–Teller (BET) method, Ramen spectra and Zeta potential measurement, photocatalytic properties, as well as active species trapping experiments. XRD and XPS show the as-prepared powder is nitrogen-doped simonkolleite Zn5(OH)8Cl2H2O (DSM) with a small ZnCl2 fraction. SEM investigation indicates that the as-prepared powder possesses a flower-like layered shape. The UV–Vis–NIR exhibits that after doping, the DSM possesses strong light absorption in the ranges of 300–500 and 1400–2500?nm, a direct electronic transition with a band gap energy of 2.469?eV. PL measurement reveals a strong photoluminescence and an up-conversion from lower to higher-energy visible light in as-prepared samples. Zeta potential investigations show that during photocatalysis, the charges on as-prepared photocatalyst are positive. The photocatalytic experiments show a good dark adsorption, a high photodegradation (99.4% at 60?min), a high pseudo-first-order constant (k) of 0.0261?min?1. Meanwhile, the active species trapping experiments suggest that hole (h+) is the dominant active species during photocatalysis. It is concluded that the doping favors in enhancing vis-light-photocatalysis. This work makes a significant contribution to the literature.
关键词： photocatalyst,nitrogen-doped simonkolleite,visible-light photocatalysis,photoluminescence
更新于2025-09-09 09:28:46
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Dual-Bandgap Effect of Photonic Crystals on TiO2 Photocatalytic Activity in Ultraviolet and Visible Light Regions
摘要： Photonic crystals (PCs) have promising characteristic to raise the light harvest of materials. PCs with one photonic band gap (PBG) were usually used to enhance the light harvest of materials. In this research work, we used PCs with dual PBGs to increase the light harvest. SiO2 PCs with dual PBGs were constructed through depositing a SiO2 PCs layer on another SiO2 PCs layer by vertical deposition method. Then the bi-layer structured SiO2 PCs were composited with nanocrystalline TiO2 film which was sensitized by CdS quantum dots (QDs) (Q-T), to produce photocatalyst for photodegradation of gaseous acetaldehyde. By adjusting the PBGs of the bi-layer SiO2 PCs, namely one PBG matching with the absorption edge of TiO2 and another PBG matching with the absorbing range of CdS QDs, the photocatalytic activity of the composite film under white light irradiation was increased to 2.11 times of that of the control photocatalyst (the Q-T film coated on a disordered porous SiO2 film). When Q-T film was coupled with a monolayer SiO2 PCs, which has single PBG centered at TiO2’s electronic band gap (EBG) of 380 nm, its photocatalytic activity was increased by 1.34 times. When coupled with a monolayer SiO2 PC with the PBG centering at the EBG of CdS QDs (465 nm), the photo-catalytic activity of the Q-T film was increased by 1.54 times. Because the SiO2 PCs with dual-PBGs can simultaneously enhance the light harvest in ultraviolet and visible light region, the Q-T film coupled with dual-PBGs SiO2 PCs showed the highest activity.
关键词： Photocatalyst,SiO2 Opal,Dual photonic band gaps,TiO2,Photonic crystals
更新于2025-09-09 09:28:46
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Systematic Optimation of Promoters in Trace SnS2 Coating SnO2 Nano-Heterostructure for High Performance Cr(VI) Photoreduction
摘要： Constructing heterojunction semiconductor materials with a strong interfacial interaction are emerging as a forefront material with excellent photocatalytic performance. Herein, we report a novel SnS2/SnO2 heterojunction material via in-situ trace vulcanization strategy to coating SnS2 on the SnO2. The thickness of the coating layer can be regulated by controlling the content of SnS2. Moreover, The molar ratio of S to Sn, particle size of SnO2 precursor and vulcanization time associated with the SnS2 content of heterojunction catalyst were controlled to optimize photocatalytic performance. SnS2/SnO2 heterojunction catalyst with 19.5% SnS2 content delivered a ultrahigh visible-light activity in Cr(VI) degradation, remarkably superior to the inert SnO2 precursors and full-vulcanized SnS2 under identical testing conditions. Amazingly, the enhanced interfacial interaction can remarkably enhance the separation and transfer of photogenerated charges. The systematic methodology of interface regulation in SnS2/SnO2 system is first reported in this work, which would promote the understanding of nano-heterojunction material for high-performance water treatment application.
关键词： Interfacial Interaction,Photovoltage,Photocatalyst,Nano-heterojunction,In-situ Vulcanization
更新于2025-09-09 09:28:46
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Microstructure and photocatalytic performance of BiVO4 prepared by hydrothermal method
摘要： Monoclinic BiVO4 photocatalyst was hydrothermally synthesized at different pH conditions without surfactant. The microstructure and photocatalytic behavior of as?prepared samples were characterized by X?ray diffraction, scanning electron microscope, transmission electron microscopy, UV?vis diffuse reflectance spectra, electrochemical workstation and dye degradation experiment. The results show that the pH value had a significant influence on the microstructure and photocatalytic performance of BiVO4. In acid environment, heavy precipitation of tetragonal BiVO4 took place in a short time at room temperature, whereas only amorphous powders formed as the pH value was equal or higher than 7. The monoclinic BiVO4 gradually nucleated and grew at the early stage of synthesis procedure at 180°C, and finally became the unique crystalline phase. The relationship between microstructure and photocatalytic activity the photocatalyst was well discussed. It is observed that the BiVO4 prepared in the neutral condition (pH 7) exhibited desirable photocatalytic degradation efficiency toward Rhodamine B solution, mainly due to the efficient separation of photogenerated electron?hole pairs and enhanced visual light absorption during degradation process, which were ascribed to the comprehensive function of high exposed {010} crystal facets, close packed structure, small particle size, and special floating characteristic.
关键词： BiVO4,microstructure,photogenerated electron?hole pairs,photocatalyst,photocatalytic activity
更新于2025-09-09 09:28:46
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doping
摘要： Results obtained on the visible light mediated photocatalytic properties of Al2O3 nanoparticles doped with Zn2+ ions synthesized by precipitation method is given in this paper. XRD, SEM, TEM, XPS, FT-IR and PL studies were performed to bring out the properties of the synthesized nanoparticles. Peaks related to monoclinic Al2O3 (θ -phase) was observed from the XRD patterns of the undoped and doped samples. A decrement of band gap from 3.86 eV to 3.71 eV with Zn doping has been observed. Oxygen vacancy related peaks were observed in the PL spectra of the samples. Enhanced degradation efficiency through Zn-doping has been observed for the Al2O3 nanoparticles against methyl orange. The maximum degradation efficiency of 90.69% observed for the 4 wt% Zn-doped Al2O3 catalyst was well acknowledged from its maximum degradation rate constant of 0.0273 min?1. The more stable nature of the Zn-doped Al2O3 photocatalysts confirmed their use as efficient photocatalysts for practical applications.
关键词： Photoluminescence,Doping,Photocatalyst,Visible light
更新于2025-09-09 09:28:46
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Fabrication of Opaline ZnO Photonic Crystal Film and its Slow Photon Effect on Photoreduction of Carbon Dioxide
摘要： Monodisperse ZnO particles with adjustable size have been produced on a large scale by two-step seeding-growth polyol reactions. Through spin coating of supersaturated ZnO/DEG solution and evaporation of solvent, opaline ZnO photonic crystal (PC) film with good crystallinity and uniform photonic structures can be prepared from these ZnO particles. Compared with a disorderly stacked ZnO film, the ZnO PC film shows higher activity in photocatalytic reduction of CO2 because of the generated slow photons at the edge of photonic bandgap and their promotion to the light absorption. When the electronic bandgap of ZnO matches the red-edge of photonic bandgap of ZnO PC, the enhancement factor of photocatalytic activity represented by CO evolution can be maximized to 2.64 fold in current experiment. Compared to the traditional inverse opal photocatalysts, the opaline ZnO photocatalysts are prepared by simplified and scalable procedures and they still possess the same enhancement in activity compared to ZnO without photonic structure, which might be broadly used in solar energy utilization, environment protection and many other green chemical processes in the future.
关键词： Photocatalyst,Slow photon effect,Photonic crystal,Reduction of CO2,ZnO
更新于2025-09-09 09:28:46
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Combined adsorption process and photocatalytic degradation of some commercial herbicides over N-doped TiO <sub/>2</sub> particles supported on recyclable magnetic hexagonal mesoporous silica
摘要： Magnetic hexagonal mesoporous silica (magnetic HMS) containing N-doped TiO2 was prepared by hydrothermal method and used for the removal of trifluralin, 2,4-dichlorophenoxyacetic acid, and glyphosate herbicides at the presence and absence of UV/visible lights. The prepared samples were found as efficient for the removal of the herbicides and easily recyclable after treatment by UV irradiation. A red shift effect by nitrogen doping was also observed in the prepared samples resulting photocatalytic activity at the presence of visible light. Kinetic studies indicated that the photodegradation followed as the first order and kUV ≈ 10kvis. The results also showed synergetic effects between the adsorption of herbicides on the surface of magnetic HMS and photoreactions over N-doped TiO2 species.
关键词： nitrogen doping,titanium oxide,herbicide,HMS,Photocatalyst
更新于2025-09-09 09:28:46